Biodiversity of the wetlands of the Kakadu Region, northern Australia

Abstract

The biodiversity values of the wetlands in the Kakadu Region of northern Australia have been recognised as being of national and international signifi cance, as demonstrated through their listing by the Ramsar Convention on Wetlands. Analyses of the wetland biodiversity have resulted in the production of species list for many taxa, and some population and community-level analyses of biomass and abundance, and the mapping of habitats at multiple scales. Wetland habitats include inter-tidal mud-fl ats, mangroves, hyper-saline fl ats, freshwater fl ood plains and streams. The tidal infl uence on the saline wetlands is pronounced, as is the infl uence of the annual wet-dry cycle of the monsoonal climate on the fl ood plains and streams. The vegetation is diverse and highly dynamic with rapid turnover of organic material and nutrients. The fauna is abundant with endemism being high in some habitats. Most fauna analyses have focussed on vertebrates with a large amount of information on waterbirds and fi sh in particular. However, despite extensive effort over the past two decades much is still unknown about the biota. While the invertebrate fauna in the streams has received some attention, a large taxonomic classifi cation effort is required. The functional inter-relationships between habitats and species have largely not been assessed. Further, the ecology of many species is only cursorily known. At the same time there has been increased attention to pressures on the wetlands, such as weeds and feral animals, water pollution, and the potential impact of climate change and salinisation of freshwater habitats. Importantly, given the social context of the region, increased attention is being directed towards traditional use and management of the wetlands.

Can hydrologic management practices of rice fields contribute to macroinvertebrate conservation in southern Brazil wetlands?

“…The arthropods, mainly aquatic insects, accounted for most of the taxa found in the studied rice fields. The predominance of the aquatic insect families was also verified in wetlands of southern Brazil (Stenert & Maltchik, 2007;Stenert et al, 2008), Pantanal (Heckman, 1998), countries of the northern hemisphere (Wissinger, 1999;Heino, 2000), and Australia (Finlayson et al, 2006). However, the macroinvertebrate composition in the rice fields was different from that on wetlands mainly due to the high dominance of oligochaetes, which represented the majority of the individuals collected (70.6%).…”

Mapping Aquatic Vegetation in a Tropical Wetland Using High Spatial Resolution Multispectral Satellite Imagery

“…The method is temporally transferrable, having been used to map vegetation on the Magela Creek floodplain for subsequent years 2011-2013 with only minor adjustments to thresholds to account for spectral variation due to slight differences in view angle and seasonality [47]. One way to test whether the method is spatially transferrable would be to apply it other wetlands in the region, which are quite different in composition [29].…”

“…Woodland communities have 10%-50% woody cover, whereas open forest communities have 50%-70% cover. These communities are typically inundated for 5-8 months of the year [29]. The Oryza grassland class is dominated by the annual grass, Oryza meridionalis towards the end of the Wet season.…”

“…Major ecological weeds are Para grass (Eurochloa mutica), and Salvinia molesta. Previous research has identified 10 major vegetation communities within the Magela Creek floodplain [33], the species composition of most communities can be seasonally dynamic [29]. The most recent community level vegetation map for the whole of the Magela Creek floodplain was based on time series (May-September 2006) Landsat 5 TM satellite imagery [9].…”

Cornerstones of biodiversity conservation? Comparing the management effectiveness of Kruger and Kakadu National Parks, two key savanna reserves

“…However, the preparation of a new management strategy for feral animals in Kakadu (see Field et al 2006) provides an opportunity to tackle some of these issues and improve feral animal management. That strategy recommends control within an adaptive management framework in conjunction with the use of a spatio-temporal animal reduction (STAR) model designed to incorporate ecological and economic factors into decisionmaking.…”